I'd say the blind part of the faith kicked in when the Markab decided to ignore the medical study of the disease that said it would spread faster if they were in much tighter contact with each other and up and all move into one big room with each believing that being isolated from everyone else would show God that they were all holy and thus they'd be spared the disease.

Whenever one ignores other points of reality for sake of wanting something to be a certain way, wrapped up in a pious wrapper, would usually constitute blind faith, I'd say.